Fluid motor



FLUID MOTOR Filed July' 14, 1939 2 Sheets-Sheet l INVENTOR. /VO/v wpa/7] A TTORNEY.

M. KRAUT pr 22, E..

FLUID MOTOR Filed July 14, 1939 2 Sheets-Sheet 2 ypipe I3.

Patented Apr. 22, 1941 Y UNTED STATES i PATENT OFFECE FLUID MOTCIR Max Kraut, San Francisco, Calif.

Application July 14, 1939, Serial No. 284,513

3 Claims.

My invention relates to reciprocating motors adapted to be operated by fluid under pressure.

An object of my invention is to provide an erlicient fluid operated reciprocating motor.

Another object is to provide a fluid motor capable of a power stroke of considerable length.

, Another object is to provide a fluid motor capable of reciprocating at a very rapid rate.

Another object is to provide in a reciprocating iluid motor a fluid-tight movable wall of improved construction.

Still another object of the invention is to provide a fluid motor which is of practical construction and is of long life.

These and other apparent objects I attain in a manner which will be clear from consideration of the following description taken in connection with the accompanying drawings, of which:

Fig. 1 is an elevational view in cross-section of one form of my fluid motor.

Fig. 2 is a sectional view of the motor of Fig. l taken on the line 2 2, as indicated.

Fig. 3 is an elevational view in cross-section of an alternative form of my fluid motor.

Fig. 4 is an elevational View in cross-section of an alternative form of fluid motor.

Fig. 5 is a sectional view of the motor of Fig. 4 taken on the line 5 5, as indicated.

In the embodiment of my invention illustrated in Fig. 1, a cylindrical housing I has, at the top, a ilange II to which is attached a cap I2, and, at the bottom, is preferably formed with a conical portion to which is connected a fluid outlet The housing It has a fluid inlet I4 ope-ningthrough the side wall thereof into the chamber within and to which is connected a fluid inlet pipe I5. The upper Wall of the chamber is movable and, in the embodiment of Fig. 1, comprises a piston I6 which is mounted to slide in the housing It above the inlet Id and is secured to a centrally located tube I'I by means of a retaining nut I8 which is in threaded engagement with Vthe tube II and which holds the piston tightly against a shoulder 28 on the tube I'I.

Slidably mounted on the tube II below the pisrton I is a valve structure comprising a sleeve 2! carrying a valve element 22 clamped between the outwardly extending upper portion of the sleeve 2I and a retaining nut 23 in threaded engagement with the sleeve ZI. The valve element 22 may be of any suitable material, metallic or otherwise. The valve element 22, however, is preferably made of rather stiff rubber or composition material, `of sufficient flexibility to seat its motion. Preferably the valve element seats against a conical seat 24 forming part of the housing I I) and loc-ated below the inlet I4. A tension spring I9 surround the tube I1, is attached to the nut I8, as by Welding at A, and is also attached to the sleeve 2 I, as by welding at B.

The tube I 'I extends upwardly from the piston it and is guided in a bushing 25 held in the upper part of the cap I2. Resting on the cap I2 is a spring abutment 26 against which presses a spring 21 abutting at its upper end a spring abutment 28 which is adjustably retained by an adjusting nut 30 in threaded engagement with the upper end of the tube II. Slidably disposed within the tube I'I is a rod 3I which is threaded at its top end and carries a nut 32 which rests on the top of the tube I'I. The rod 3| projects downwardly from the lower end of the sleeve 2I and the nut 23 and exten-ds out through the outlet pipe I3.` In the operation of the device the rod 3| is reciprocated up and down and whatever it is desired to reciprocate is attached to the lower end of the rod 3I, although it may, of course, be attached to the top of the rod 3I, if desired. The

motor is adapted to be operated in conjunction with a load connected to the rod 3| in such a manner that a downward force is exerted by the load on the rod 3l. At a distance below the nut 23, comparableto the desired length of stroke, is located the top of a valve engaging member 33 which is attached to the rod 3I for movement therewith. At a certain stage in the upward stroke of the rod 3I, the member 33 is adapted to engage the lower face of the nut 23 and lift the valve element 22 on its seat 24. The distance between the top of the member 33 and the ybottom of the nut 23 is less than the permissible upward travel of the piston It. An overflow passage 34 is formed at one side of the housing IU and connects with the space above the piston I 6 and with the fluid outlet to provide a way of escape for iluid which may leak past the piston I6, and also to equalize the pressure in the space above the piston and the space below the valve.

In describing the operation of the motor it will lbe assumed that a downwardly directed load exists on the rod 3I, which may be due to a spring, a weight to be reciprocated, or other means depending upon the use to which the motor is put. At the start of operation, then, the parts of the motor will be as represented in Fig. l, withfthe valve element 22 seating on the seat 24, and the spring 2l supporting therod 3I against the downwardly directed forceon it. `Fluid. under pressure is permitted to flow through the inlet I4 by opening a control valve in the inlet pipe I5, and pressure is exerted upwardly against the -iston ES and downwardly against the valve element 22. Consequently, the piston l moves upwardly, carrying with it the tube il and the rod 3 l. During the upward movement of the piston IE5, the valve element remains seated on its seat 24, closing the outlet, because of the downwardly directed fluid pressure on it. As the piston moves upward the spring is exerts an upward force on the valve element 22 tending to unseat it, and if the tension of the spring IS were made sumoiently great at the end of the desired stroke it could be made to overcome the force of fluid against the valve element 22 and cause the valve element to be unscated at a certain point in its stroke. Preferably, however, the tension of the spring I9 is not sumcient to overcome the force of fluid against the valve element 22 and the valve element remains seated until the member 33 engages the nut 23 and lifts the valve element 22 ofi its seat 2t. When the valve element 22 lifts, fluid is permitted to iiow past the valve through the outle-u and there is a momentary collapse of fluid pressure in the chamber. The instant that iluid has access to the under side of the valve element 22, the resultant force of fluid on the valve element 2 largely disappears and the spring lil jerks the valve element 22 upward. From the instant of cracking the valve, the action is cumulative, with the result that the valve opens wide very quickly and there is a very rapid decrease of pressure within the fluid chamber. Upon collapse of the uid pressure within the chamber, the downwardly directed force on the rod 3| pulls the rod 3l, the tube Il', the piston it and the valve element 22 downwarlly until the valve element seats on the seat 2%, closing the fluid outlet. Pressure immediately starts to build up in the chamber and raises the piston I6 upwardly to start another cycle of reciprocatory motion.

The length of stroke may be adjusted by varying the position of the nut 32 on the rod 3l and the rapidity of reciprocation may be controlled by adjusting the pressure of fluid supplied to` the motor through control of a valve in the inlet pipe I5.. The compression of spring 21 may be adjusted for different loads on the rod 3l by varying the. position of the nut 3i) on the tube I'I.

An alternative form oi my motoris illustrated in Fig. 3. In this form the movable upper wall of the fluid chamber is connected in a iluid tight manner with the housing cl2 by means of a bellows d which construction issubstituted for the piston I6. The bellows lil is preferably made of a exible material such as rubber and has an outwardly directed flange 4I at the top which is clamped between the flange of cylindrical housing 42 and the cap l2. The housing 42 may be similar to the housing IG of the motor of Fig. 1 except that the passage 3Q is omitted. The cap i2 is the same as in Fig. 1 except that a hole d3 therethrough is provided to maintain atmospheric pressure above the bellows All). The bellows 4l) preferably terminates at the lower end in an inwardly directed ilange 44 which is clamped between a metal plate 45 and a ring 46 b-y bolts 41. The plate 45 is secured to the tube I7 by being clamped between a shoulder on the tube I'I and the nut I8 in threaded engagement with the tube.V The bellows 43 are preferably molded with a corrugated axially `extending wall and laterally rigid rings 48, preferably of metal, are placed inside the bellows, one ring in each of the outwardly directed folds` of the corrugated wall. The action of the rings is to prevent the inward lateral collapse of the bellows when fluid pressure is exerted in the space below and around the outside of the bellows. The only substantial motion of the bellows, therefore, is one in the axial direction. The remainder of the motor of Fig. 3 may be the same is in that of Fig. 1. In operation, the motor of Fig. 3 is similar to that of the motor of Fig. l, the wall being acted upon by the fluid under pressure to raise the tube I3 and the rod 3l just as the piston I6 in the motor of Fig. 1 is' acted upon to accomplish the same result. The construction of Fig. 3 has the advantage over the piston I6 that no leakage of fluid from the fluid chamber can occur.

Another alternative construction is illustrated in Figs. 4 and 5. In this form, a cylindrical housing 5D is employed, having a cover plate 5I secured to one end thereof and a cover plate 52 secured to the other end thereof. As oriented in Fig. 4, the space within the housing is divided into upper and lower parts by a partition 53 having a central hole therein. Above the partition 53, a fluid inlet pipe 54 connects with the space within the housing and is connected to a supply of fluid under pressure. Below the partition 53 a iluid outlet pipe 55 is connected with the spa-ce within the housing. A piston 56 fitting the inside of the housing 50 above the inlet 54 is adapted to slide up and down within the housing. A cup leather 5l is preferably secured to the face of the piston 56. The piston is clamped on an axially extending rod 58 against a shoulder 60 thereof by a nut 6I in threaded engagement with the rod 53. In this embodiment, the motor carries within itself a loading spring S2 for eecting return of the piston and is not dependent upon any outside load. The 4spring 52 surrounds the rod58 and bears downwardly onthe piston 55 and upwardly aga-inst an abutment 63 which is piloted on the rod 58 and is adjustably retained in position by the screw 6 4 whichY passes through the cover plate 5I in threaded engagement therewith. A lock nut 65 in threaded engagement with the screw 64 locks the screw B4 in fixed position. The rod 58 ypasses slidably through a hole in the screw 64 and may be connected to any member or device which it is desired to reciprocate.

The upper edge of the hole in the partition 53 is beveled to form a valve seat 5l. Adapted to seat on the seat BI and extending through the hole in the partition 53 is4 a valve element 68 slidably mounted on the rod 58. The valve element 68 abuts a shoulder lll on the rod 5,8 in the lowest position of the piston 5.6i. Abutting a shoulder .on the lower portion of the valve element G8 is a member II which is retained by a nut 'l2 in threaded engagement with the, threaded lower end of the valve element 6,3. The member 'll has upwardly extending projections 'I3 at intervals oircumferentially.therearound and has a downwardly extending rim for retention of a compression Vspring 'i4 abutting the member ll. The rod 58 extends downwardly through the valve element 68 and through the cover plate 52 and carries threaded on its threaded lower end an adjusting nut in the form of a sleeve "I5 which is adapted to slide in a bushing i6 mounted in the cover plate 52. A lock nut 'I9 is also threaded on the rod 53. VThe upperend of the sleeve .nut l5 engages a member 'I'I which is slidableon the rod 58v and which has a turned up rim within which is disposed the lower end of the spring'M abutting the member TI. It is evident that any member or device to be reciprocated may, if desired, be attached to the lower end of the rod 58 instead oi the upper projecting portion thereof. A hole 18 may be located in the housing above the uppermost position of the piston 56 for connecting the space above the piston with the atmosphere and for permitting escape of fluid which may leak past the piston 56.

In operation, the parts of the motor are normally in the positions shown priorto admission of iluid. When fluid under pressure is admitted through the inlet 54, it acts on the under side of the piston 56 to force it up-ward and on the valve element '68 to hold it tightly against its seat 6l. As the piston 56 moves upward, carrying the rod 58 with it, the spring 62 is compressed, and the member 11 is moved upwardly tow-ard the member 1I. Duringr the upward movement of the piston the valve is held closed by fluid pressure, in spite of .the upward force on the valve element 68 exerted by the spring 14, until the member 'Vl engages the member 'H and lifts the valve element 68 off its seat. As soon as uid gets to the under side of the valve element 68 and equalizes the fluid pressure on both sides thereof, there is nothin-g to hold the valve element down, and as a result the valve element 68, the member 1l, and the nut 12 are y immediately forced upward by action of the compressed spring 14 in such manner that the valve opening is suddenly increased and there is an instantaneous drop of pressure below the piston 56. It will be seen that in the embodiment of Fig. 4, the valve element, after being lifted od its seat, is pushed to a wide open position, while in the embodiment of Fig. 1, it is pulled towide open position. The valve element 6B continues upwardly until the projection-s I3 on the member 'H stop against the under si-de of the partition 53. In this position, fluid passes from the inlet 5d through the valve opening in the partition 53, through the openings between the projections i3, and out through the outlet 55. When the drop in pressure below the piston occurs, the spring 62 forces the piston 55 downwardly, the shoulder 1i) engages the valve element 68, and forces the valve element 68 downwardly until the parts all come to rest in the positions shown in Fig. 4. Fluid pressure immediately builds up, forces the piston 55 upwardly and the cycle is repeated indefinitely. It is apparent that as the piston 56 moves up and down in the cylinder 50 the rod 58 also moves, carrying with it the member or device to be reciprocated. Thek length of stroke may be varied by adjusting the position of the nut 15.

If desired, a bellows similar to that shown in Fig. 3 may be employe-d in Vplace of the piston 56 in the motor of Fig. 4.

All of the forms of my motor disclosed herein may be operated by use of either gas or liquid as the operating uid. My motors are found to be capable of very rapid reciprocation. An important feature of my motors is that they are capable of causing reciprocation through a stroke of considerable length, and that during this stroke a great force can be exerted by the reciprocating parts.

It will be understood that the design and construction of my motors and the parts thereof may be varied widely without departing from the spirit and scope of the invention as defined in the appended claims.

I claim as my invention:

l. A reciprocating fluid motor comprising: walls forming a chamber provided with an inlet and an outlet for uid, one of the walls of said chamber being movable; a reciprocable member moved by said movable wall; a valve structure including a valve element adapted to normally close said outlet; means associated with said reciprocable member and adapted, at a certain stage in the travel of said movable wall away from said valve element, to positively engage said valve structure to move said valve element and open said outlet; and a tension spring within said chamber having one end connected to move with said reciprocable member and the other end connected to said valve structure, whereby said valve element is pulled toward said movable wall at the moment of opening said outlet.

'2. A reciprocating iiuid motor comprising: walls forming la chamber provided with an inlet and an outlet -fo-r iiuid, one of the walls of lsaid chamber being movable; a tube connected to said movable wall for movement therewith; a valve structure slidable on the exterior of said tube and includ'ing a valve element adapted to normally close said outlet; a rod adjustably carried in said tube; a member attached to said rod on the opposite side of said valve element from said movable wall 'and spaced from said valve structure; and a spring disposed between said movable wall and said valve element and having one end connected for movement with said tube and the other end connected for movement with said valve elemnet.

3. A reciprocating uid motor comprising: walls forming a chamber provided with an inlet and an outlet for fluid, one of the walls of said chamber being movable; a reciprocable member secured to said wall and extending through said outlet; a

valve structure slideable on said reciprocable member and including a valve element adapted to normally close said outlet; a member secured to said reciprocable member on the opposite side 

